WASHINGTON - President Bush's hopes of securing a comprehensive immigrationoverhaul have brightened considerably in the new Democratic-controlledCongress, but resistance from organized labor -- one of the Democratic Party'smost loyal constituencies -- could complicate those efforts.

The AFL-CIO, which represents 53 unions with more than 9 million members, isratcheting up opposition to a temporary guest worker program, a key element ofBush's immigration plan. At the same time, two powerful unions in a breakawaylabor coalition, Change to Win, have tended to support the provision.

The divisions within labor were evident during the contentious debate overimmigration in the previous Republican-controlled Congress. But they take onheightened significance as Democrats assume control of the 110th Congress andbegin shaping the legislative agenda.

Labor political action committees contributed 86 percent of their donations toDemocratic candidates, a total of $42 million, according to the Center forResponsive Politics. Labor also aggressively waged get-out-the-vote efforts andother activities to help end 12 years of Republican control of Congress.

With its bolstered political clout, the AFL-CIO is better positioned to confronta powerful coalition of business groups that is pressing for a temporary workerprogram to bring in thousands of foreign workers each year.

"The industry will oppose a bill that doesn't have a good temporary workerprogram in it," said Randel Johnson, vice president of the U.S. Chamber ofCommerce.

But Johnson acknowledged that the AFL-CIO's heightened political stature in theaftermath of the elections raises the challenge for his side.

"In view of the election, it's very significant," he said. "Certainly, theAFL-CIO has a bigger seat at the table than they did before."

Business leaders say the guest worker program is needed to bring in foreignworkers to fill unskilled and low-skilled jobs Americans don't want. AFL-CIOofficials say the program is designed to give business a steady source of cheaplabor and would take jobs from U.S. citizens.

"We don't believe our elected representatives are ready to adopt legislationthat creates paths for corporations to import workers (and) reduce workingstandards in the United States," said Ana Avendando, associate general counselfor the AFL-CIO. "That's exactly what guest worker programs are."

Bush has made immigration one of his top domestic priorities since the outset ofhis presidency. But he was rebuffed by members of his own party whenconservative Republicans in the House of Representatives effectively bottled upa Senate-passed bill. The legislation, which had bipartisan support, included aguest worker program and a legalization plan to put millions of undocumentedworkers on a path to U.S. citizenship.